Anaerobes (from chart) Flashcards
General features of anaerobes
- Mixed infections
- remove toxic O2 forms
- fermentation
Anaerobes live at _____
low redox potential (generated by other organisms)
Anaerobes produce ______
abcesses
Anaerobes (general) virulence factors?
- Normal flora that enter unprotected areas
- anaerobiosis either exits or generated by other organisms
- tissue destructive enzymes -> abcesses
Common anaerobic abcesses…
- Abdominal
- Salpingitis
- Lung
- URT
- Brain
All anaerobic organisms
- Bacterioides fragillis
- Prevotella melaninogenica
- Porphyromonas gingivalis
- Fusobacterium
- Peptostreptococcus
- Propionibacterium
- Clostridium (bot, tet, perf, diff)
Anaerobic Gram Negative bacteria
Bacterioides, Prevotella, Porphyromonas, Fusobacterium
Anaerobic Gram Positive bacteria
Peptostreptococcus, Propionibacterium, Clostriduim
Anaerobe bacteria treatment
Drainage*
PenG
Metronidazole and Clindamycin
*Drainage allows O2 in
PenG not given to _____ and _____
Because they are ______________
Bacterioides and Prevotella
Beta-Lactam resistant
2nd line Antibiotics for Anaerobes
2nd and 3rd gen Cephalosporins and Carbapenems
Bacterioides Structure
Gram - Rod
Bacterioides features
60% of abdominal bacteria
Can live as monoculture
Bacterioides clinical
- Colonic
- 70% of anaerobic bacteremia
Most common
Bacterioides virulence
- Antiphagocytic capsule
- Enzyme production
- LPS
Bacterioides enzymes
- SOD and Catalase
- Neuraminidase and Heparinase
Prevotella Structure
Gram - Coccobacillus
Prevotella clinical
- Oral
- Brain and Lung abcesses
Prevotella enzymes
Collagenase
Porphyromonas structure
Gram - Rod
Porphyromonas Clinical
- Oral
- Gingivitis
- Oral Abscess
Carriers of Porphyromonas
Warm and moist areas
-Axilla, groin, perineum
Fusobacterium structure
Gram - fusiform
Fusibacterium locations
Oral and Colonic
Fusibacterium Clinical
Infectious monoculture in osteomyelitis
Peptostreptococcus structure
Gram + coccus
Peptostreptococcus locations
Bacteremia
Pleura/lungs
Propionibacterium acnes structure
Gram + pleiomorphic rod
Propionibacterium location
-Skin (acne)
-Brain (abcess)
Clostridium Structure
Gram + rounded ends
in pairs or short chains
Clostridium bacteria are _______ and _________
Spore-formers
Strict anaerobes
C. Botulinum clinical features
Flaccid paralysis (descending)*
-Dysphagia, Diplopia, Ptosis
*Starts with Cranial Nerves
C. Botulinum Carriers
- Home-_canned_ foods
- Honey (floppy baby syndrome)
- Wounds
C. Botulinum Serotypes
A, B, E
C. Botulinum virulence
AB Neurotoxin
- B binds to Motor Neuron End plate
- A prevents ACH vesicle fusion
C. tetani incubation time
4d - 4 w
C. tetani clinical
Rigid paralysis
- trismus, ophisthotonos
- death- from spasm interefering with respiration
C. tetani carriers
Spores from penetrating fomites
Umbilical stump in neonatal tetanus
C. tetani virulence
AB neurotoxin*
- B binds to NMJ
- A retrograde transported to presynaptic inhibitory neuron
- Inhibit GABA release
*plasmid encoded tetanospasmin
C. perfringens features
5 histotoxic strains
Others cause myonecrosis
C. Sordelli causes…
Postpartum infection
C. perfringens incubation
1-3 days infected wound suppurating
C. perfringens clinical
Foul discharge, necrosis, toxemia, shock, death
C. perfringens can also cause _____
Enteritis Necroticans (food poisioning)
**if ingested orally
C. perfringens carriers
spores (in food poisioning)
Injury to tissues
Ischemia (anoxic environment)
*Polymicrobial if others use O2 to reduce oxygen presence
C. perfringens virulence factors
a-toxin (phospholipase)
b-toxin (enteritis necroticans)
Hyaluronidase
Enterotoxin
C. perfringens virulence effects
Leukocytosis
gas fermentation–> tissue distension–> vascular compression–> ischemia–> necrosis–> toxemia
C. diff incubation
4-10 days secondary to Rx treatment
Drugs that carry C. diff risk
Broad spec clindamycin
prolonged use of PPI
C. diff clinical
May affect entirety or part of colon (= early watery diarrhea)
Pseudomembrane – leukocytes penetrate gut epithelium and form white-yellow exudate
C. diff carriers/origin
Normal flora (impt for Treg development)
Antibiotics (disrupt flora)
DIsseminated in diarrhea
Nosocomial – 94%
C. botulinum Tx
Trivalent (ABE) or Polyvalent Antitoxin immediately
NO AB because not infection
C tetani vaccine
Tdap + boosters
C. tetani Tx
-TIg antitoxin (early!)
–Tracheostomy
- Muscle relaxant (MgSO4)
- Metronidazole
C. perfringens Tx
Amputation & Debridement
Penicillin, Metronizadole, Clindamycin
C. diff Tx
- Stop Antibiotic, replinish flora
- fluids
- Anti-Toxin B Antibodies
- Vancomycin, Metronidazole
- Fidaxomicin
- Fecal replacement therapy